Your face, my thane, is as a book where men / May read strange matters.
Act I, Scene 5 · Lady Macbeth
Context
When Macbeth arrives, Lady Macbeth immediately warns him that his face reveals too much of his inner turmoil about the prophecy and what it might require.
Analysis
The book simile positions Macbeth's face as a readable text, giving others interpretive power over him. Lady Macbeth's warning implies he lacks control over his own outward signs—that his body betrays him by publishing 'strange matters' he wants kept private—which makes deception something he must learn rather than something he naturally possesses.
Essay Tip
Use this to argue that Shakespeare presents Macbeth as dangerously transparent—his face 'reads' his guilt before he's even committed a crime, suggesting his unsuitability for the deceit that power requires and explaining why Lady Macbeth must script his performance.